1. Field of the Invention
The present invention relates to an organic light emitting element, a display apparatus and a method of manufacturing the display apparatus. More particularly, the present invention relates to an organic light emitting element capable of improving an image display quality, a display apparatus capable having the organic light emitting element, and a method of manufacturing the display apparatus.
2. Description of the Related Art
An information processing device has been improved, and has been widely used in various fields.
Data processed by the information processing device is an electric signal or a coded signal. However, a user may not directly recognize the electric signal or the coded signal. The information processing device has a display apparatus so that the electric signal or the coded signal is displayed by the display apparatus.
The display apparatus is classified into an emissive display apparatus and a non-emissive display apparatus. The emissive display apparatus displays the image using luminescence. The emissive display apparatus includes a cathode ray tube (CRT) display apparatus, a plasma display panel (PDP), a light emitting diode (LED), an inorganic light emitting display apparatus, an organic light emitting display (OLED) apparatus, etc.
The non-emissive display apparatus displays the image using reflection, scattering or interference of a light. The non-emissive display apparatus includes a liquid crystal display (LCD) apparatus, an electrochemical display (ECD) apparatus, an electrophoretic image display (EPID) apparatus, etc.
The inorganic light emitting display apparatus and the OLED apparatus have been widely used.
Electrons are accelerated in a light emitting portion of the inorganic light emitting display apparatus in strong electric field so that the accelerated electrons are combined with inorganic material, and the inorganic material is in an excited state. When the excited material is changed into a ground state, a light is generated in the light emitting portion.
The OLED apparatus has an organic light emitting layer formed between an anode electrode and a cathode electrode. Electrons from the anode electrode are combined with holes from the cathode electrode in the organic light emitting layer so that molecules of the organic light emitting layer are in the excited state. When the excited molecules are changed into the ground state, the light is generated in the organic light emitting layer.
The organic light emitting layer of the OLED apparatus may be formed through a screen printing method or a spray printing method. In the screen printing method, organic light emitting material is printed on a substrate through openings of a mask.
In the spray printing method, the organic light emitting material is dropped on a portion of the substrate. In particular, a bank is formed adjacent to the anode electrode that is formed on the substrate, and the organic light emitting material is dropped in a space formed by the bank. The dropped organic light emitting material is dried to form the organic light emitting layer.
When the organic light emitting material is dropped on the bank that has higher surface energy than the anode electrode, the organic light emitting layer may be formed on the bank so that the image display quality is deteriorated. When the bank has higher surface energy than the anode electrode, the bank has higher adhesive force than the anode electrode.
Surface structure of the bank may be changed to decrease the surface energy of the bank through an addition process. However, when the organic light emitting layer has a double layered structure having a hole injection layer and a light emitting layer formed on the hole injection layer, the surface energy of the bank may be changed after the hole injection layer being formed. When the light emitting layer is formed after the hole injection layer being formed, the surface energy of the bank is increased so that the light emitting layer may be attached to the bank. Therefore, the image display quality of the OLED apparatus may be deteriorated.